HOW the UV blocking is achieved (for purposes of the class) is irrelevant. Nor is a debate as to HOW the standard is/was determined - or whether or not it is "arbitrary" for the purposes of the class, irrelevant. You see, that's the difference between a company sponsored class and a PPFA sponsored class. Marketing "hype" plays no part in the factual basis of the class. Sure, Tru Vue may (currently) make the only coated float glass product that meets the standard - but it is NOT the only option and the class makes this FACT perfectly clear. It isn't about whose product "looks" better, cleans better, costs less, is easier to handle, etc. It's a "science" class based on FACT. And if/when the standard changes, the new standard will be used as a benchmark/reference in the class. But until it does change, the PPFA class will adhere to the standard as it is used as criteria for passing the CPF/MCPF exams.